The present invention relates generally to microfiche viewers and more particularly to such viewers wherein a preselected microfiche carrier is automatically positioned for viewing of a predetermined frame of the microfiche.
Because of the present day "information explosion," data are being accumulated at such a rapid rate that compact data storage systems are becoming ever more important. One of the most satisfactory data storage systems thus far devised is that of microfilming, wherein sheets of data, reports, books, blueprints, pictures and the like are photographed in a photographically reduced size. Typically, an entire page then requires an area of about half an inch by five-eighths of an inch. These reduced size "frames" are then suitably assembled This system results in a tremendous compaction of storage space requirements.
One of the early methods of assembling these reduced size frames was to position them, tandem-wise, on a reel of film; but this system had the disadvantage that it became difficult to have access to a single frame without somehow going through every frame that preceded it on the reel.
Another method of assembling the reduced size frames was to print related frames onto a given sheet of film; and this became known as "microfiche". In using the microfiche, a single frame is more readily retrieved when desired, providing "random access" to the desired frame.
THE MICROFICHE, DURING ITS EVOLUTION, HAS TAKEN A NUMBER OF DIFFERENT SIZES, BUT AT THE PRESENT TIME THERE TENDS TO BE A STANDARDIZATION. One of the most popular sizes is about one hundred and fifty millimeters long and about one hundred and five millimeters wide, and this size of microfiche may be designed to contain from about sixty to over one hundred frames. Another popular size for microfiche is a film that is about five inches long and about three inches wide. Other sizes are also in use.
Similarly, microfiche have taken a variety of formats, the available one hundred some frames being used for data, for titles, or for coding.
This diversity of microfiche has hindered the storing and retrieval of microfiche stored data. For example, one arrangement attached a notched metal clip to one edge of the microfiche, the notches being used for data retrieval. Another arrangement notched the actual edge of the microfiche. Still another arrangement utilized punched coding holes along the edge of the microfiche. Some other arrangements used optical approaches and still other arrangements used markings to produce a frequency signal. The main disadvantage of these arrangements was that they required additional equipment and procedures for manufacturing each type of microfiche. Since each arrangement required a different retrieval apparatus, it was extremely difficult to intermix microfiche from different sources.